swank.R

### This program is free software; you can redistribute it and/or
### modify it under the terms of the GNU General Public Licence as
### published by the Free Software Foundation; either version 2 of the
### Licence, or (at your option) any later version.
###
### This program is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public Licence for more details.
###
### A copy of version 2 of the GNU General Public Licence is available
### at <http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt>; the
### latest version of the GNU General Public Licence is available at
### <http://www.gnu.org/licenses/gpl.txt>.

### KLUDGE: this assumes that we're being sourced with chdir=TRUE.
### (If not, `swank:swank-require` will work under the circumstances
### that it used to work anyway -- i.e. the working directory is the
### swankr directory)
swankrPath <- getwd() 

swank <- function(port=4005) {
  acceptConnections(port, FALSE)
}

startSwank <- function(portFile) {
  acceptConnections(4005, portFile)
}

acceptConnections <- function(port, portFile) {
  if(portFile != FALSE) {
    f <- file(portFile, open="w+")
    cat(port, file=f)
    close(f)
  }
  ## FIXME: maybe we should support dontClose here?
  s <- socketConnection(host="localhost", server=TRUE, port=port, open="r+b")
  on.exit(close(s))
  tryCatch(serve(s), endOfFile=function(c) NULL)
}

serve <- function(io) {
  mainLoop(io)
}

mainLoop <- function(io) {
  slimeConnection <- new.env()
  slimeConnection$io <- io
  while(TRUE) {
    withRestarts(tryCatch(dispatch(slimeConnection, readPacket(io)),
                          swankTopLevel=function(c) NULL),
                 abort="return to SLIME's toplevel")
  }
}

dispatch <- function(slimeConnection, event, sldbState=NULL) {
  kind <- event[[1]]
  if(kind == quote(`:emacs-rex`)) {
    do.call("emacsRex", c(list(slimeConnection), list(sldbState), event[-1]))
  }
}

sendToEmacs <- function(slimeConnection, obj) {
  io <- slimeConnection$io
  payload <- writeSexpToString(obj)
  writeChar(sprintf("%06x", nchar(payload, type="bytes")), io, eos=NULL)
  writeChar(payload, io, eos=NULL)
  flush(io)
}

callify <- function(form) {
  ## we implement here the conversion from Lisp S-expression (or list)
  ## expressions of code into our own, swankr, calling convention,
  ## with slimeConnection and sldbState as first and second arguments.
  ## as.call() gets us part of the way, but we need to walk the list
  ## recursively to mimic CL:EVAL; we need to avoid converting R
  ## special operators which we are punning (only `quote`, for now)
  ## into this calling convention.
  if(is.list(form)) {
    if(form[[1]] == quote(quote)) {
      as.call(form)
    } else {
      as.call(c(list(form[[1]], quote(slimeConnection), quote(sldbState)), lapply(form[-1], callify)))
    }
  } else {
    form
  }
}

emacsRex <- function(slimeConnection, sldbState, form, pkg, thread, id, level=0) {
  ok <- FALSE
  value <- NULL
  conn <- textConnection(NULL, open="w")
  condition <- NULL
  tryCatch({
    withCallingHandlers({
      call <- callify(form)
      capture.output(value <- eval(call), file=conn)
      string <- paste(textConnectionValue(conn), sep="", collapse="\n")
      if(nchar(string) > 0) {
        sendToEmacs(slimeConnection, list(quote(`:write-string`), string))
        sendToEmacs(slimeConnection, list(quote(`:write-string`), "\n"))
      }
      close(conn)
      ok <- TRUE
    }, error=function(c) {
      condition <<- c
      string <- paste(textConnectionValue(conn), sep="", collapse="\n")
      if(nchar(string) > 0) {
        sendToEmacs(slimeConnection, list(quote(`:write-string`), string))
        sendToEmacs(slimeConnection, list(quote(`:write-string`), "\n"))
      }
      close(conn)
      newSldbState <- makeSldbState(c, if(is.null(sldbState)) 0 else sldbState$level+1, id)
      withRestarts(sldbLoop(slimeConnection, newSldbState, id), abort=paste("return to sldb level", newSldbState$level)) })},
    finally=sendToEmacs(slimeConnection, list(quote(`:return`), if(ok) list(quote(`:ok`), value) else list(quote(`:abort`), as.character(condition)), id)))
}

makeSldbState <- function(condition, level, id) {
  calls <- rev(sys.calls())[-1]
  frames <- rev(sys.frames())[-1]
  restarts <- rev(computeRestarts(condition))[-1]
  ret <- list(condition=condition, level=level, id=id, restarts=restarts, calls=calls, frames=frames)
  class(ret) <- c("sldbState", class(ret))
  ret
}

sldbLoop <- function(slimeConnection, sldbState, id) {
  tryCatch({
    io <- slimeConnection$io
    sendToEmacs(slimeConnection, c(list(quote(`:debug`), id, sldbState$level), `swank:debugger-info-for-emacs`(slimeConnection, sldbState)))
    sendToEmacs(slimeConnection, list(quote(`:debug-activate`), id, sldbState$level, FALSE))
    while(TRUE) {
      dispatch(slimeConnection, readPacket(io), sldbState)
    }
  }, finally=sendToEmacs(slimeConnection, c(list(quote(`:debug-return`), id, sldbState$level, FALSE))))
}

readPacket <- function(io) {
  socketSelect(list(io))
  header <- readChunk(io, 6)
  len <- strtoi(header, base=16)
  payload <- readChunk(io, len)
  readSexpFromString(payload)
}

readChunk <- function(io, len) {
  buffer <- readChar(io, len)
  if(length(buffer) == 0) {
    condition <- simpleCondition("End of file on io")
    class(condition) <- c("endOfFile", class(condition))
    signalCondition(condition)
  }
  if(nchar(buffer) != len) {
    stop("short read in readChunk")
  }
  buffer
}

readSexpFromString <- function(string) {
  pos <- 1
  read <- function() {
    skipWhitespace()
    char <- substr(string, pos, pos)
    switch(char,
           "("=readList(),
           "\""=readString(),
           "'"=readQuote(),
           {
             if(pos > nchar(string))
               stop("EOF during read")
             obj <- readNumberOrSymbol()
             if(obj == quote(`.`)) {
               stop("Consing dot not implemented")
             }
             obj
           })
  }
  skipWhitespace <- function() {
    while(substr(string, pos, pos) %in% c(" ", "\t", "\n")) {
      pos <<- pos + 1
    }
  }
  readList <- function() {
    ret <- list()
    pos <<- pos + 1
    while(TRUE) {
      skipWhitespace()
      char <- substr(string, pos, pos)
      if(char == ")") {
        pos <<- pos + 1
        break
      } else {
        obj <- read()
        if(length(obj) == 1 && obj == quote(`.`)) {
          stop("Consing dot not implemented")
        }
        ret <- c(ret, list(obj))
      }
    }
    ret
  }
  readString <- function() {
    ret <- ""
    addChar <- function(c) { ret <<- paste(ret, c, sep="") }
    while(TRUE) {
      pos <<- pos + 1
      char <- substr(string, pos, pos)
      switch(char,
             "\""={ pos <<- pos + 1; break },
             "\\"={ pos <<- pos + 1
                    char2 <- substr(string, pos, pos)
                    switch(char2,
                           "\""=addChar(char2),
                           "\\"=addChar(char2),
                           stop("Unrecognized escape character")) },
             addChar(char))
    }
    ret
  }
  readNumberOrSymbol <- function() {
    token <- readToken()
    if(nchar(token)==0) {
      stop("End of file reading token")
    } else if(grepl("^[0-9]+$", token)) {
      strtoi(token)
    } else if(grepl("^[0-9]+\\.[0-9]+$", token)) {
      as.double(token)
    } else {
      name <- as.name(token)
      if(name == quote(t)) {
        TRUE
      } else if(name == quote(nil)) {
        FALSE
      } else {
        name
      }
    }
  }
  readToken <- function() {
    token <- ""
    while(TRUE) {
      char <- substr(string, pos, pos)
      if(char == "") {
        break;
      } else if(char %in% c(" ", "\n", "\t", "(", ")", "\"", "'")) {
        break;
      } else {
        token <- paste(token, char, sep="")
        pos <<- pos + 1
      }
    }
    token
  }
  read()
}

writeSexpToString <- function(obj) {
  writeSexpToStringLoop <- function(obj) {
    switch(typeof(obj),
           "character"={ string <- paste(string, "\"", gsub("([\"\\])", "\\\\\\1", obj), "\"", sep="") },
           "list"={ string <- paste(string, "(", sep="")
                    max <- length(obj)
                    if(max > 0) {
                      for(i in 1:max) {
                        string <- paste(string, writeSexpToString(obj[[i]]), sep="")
                        if(i != max) {
                          string <- paste(string, " ", sep="")
                        }
                      }
                    }
                    string <- paste(string, ")", sep="") },
           "symbol"={ string <- paste(string, as.character(obj), sep="") },
           "logical"={ string <- if(obj) { paste(string, "t", sep="") } else { paste(string, "nil", sep="") }},
           "double"={ string <- paste(string, as.character(obj), sep="") },
           "integer"={ string <- paste(string, as.character(obj), sep="") },
           stop(paste("can't write object ", obj, sep="")))
    string
  }
  string <- ""
  writeSexpToStringLoop(obj)
}

prin1ToString <- function(val) {
  paste(deparse(val, backtick=TRUE, control=c("delayPromises", "keepNA")),
        sep="", collapse="\n")
}

printToString <- function(val) {
  paste(capture.output(print(val)), sep="", collapse="\n")
}

`swank:connection-info` <- function (slimeConnection, sldbState) {
  list(quote(`:pid`), Sys.getpid(),
       quote(`:package`), list(quote(`:name`), "R", quote(`:prompt`), "R> "),
       quote(`:encoding`), list(quote(`:coding-systems`), list("utf-8-unix")),
       quote(`:lisp-implementation`), list(quote(`:type`), "R",
                                           quote(`:name`), "R",
                                           quote(`:version`), paste(R.version$major, R.version$minor, sep=".")))
}

`swank:swank-require` <- function (slimeConnection, sldbState, contribs) {
  for(contrib in contribs) {
    filename <- sprintf("%s/%s.R", swankrPath, as.character(contrib))
    if(file.exists(filename)) {
      source(filename)
    }
  }
  list()
}

`swank:create-repl` <- function(slimeConnection, sldbState, env, ...) {
  list("R", "R")
}

makeReplResult <- function(value) {
  string <- printToString(value)
  list(quote(`:write-string`), string,
       quote(`:repl-result`))
}

makeReplResultFunction <- makeReplResult

sendReplResult <- function(slimeConnection, value) {
  result <- makeReplResultFunction(value)
  sendToEmacs(slimeConnection, result)
}

sendReplResultFunction <- sendReplResult

`swank:listener-eval` <- function(slimeConnection, sldbState, string) {
  ## O how ugly
  string <- gsub("#\\.\\(swank:lookup-presented-object-or-lose([^)]*)\\)", ".(`swank:lookup-presented-object-or-lose`(slimeConnection, sldbState,\\1))", string)
  for(expr in parse(text=string)) {
    expr <- expr
    ## O maybe this is even uglier
    lookedup <- do.call("bquote", list(expr))
    tmp <- withVisible(eval(lookedup, envir = globalenv()))
    if(tmp$visible) {
      sendReplResultFunction(slimeConnection, tmp$value)
    }
  }
  list()
}

`swank:autodoc` <- function(slimeConnection, sldbState, rawForm, ...) {
  "No Arglist Information"
}

`swank:operator-arglist` <- function(slimeConnection, sldbState, op, package) {
  list()
}

`swank:throw-to-toplevel` <- function(slimeConnection, sldbState) {
  condition <- simpleCondition("Throw to toplevel")
  class(condition) <- c("swankTopLevel", class(condition))
  signalCondition(condition)
}

`swank:backtrace` <- function(slimeConnection, sldbState, from=0, to=NULL) {
  calls <- sldbState$calls
  if(is.null(to)) to <- length(calls)
  from <- from+1
  calls <- lapply(calls[from:to],
                  { frameNumber <- from-1;
                    function (x) {
                      ret <- list(frameNumber, paste(format(x), sep="", collapse=" "))
                      frameNumber <<- 1+frameNumber
                      ret
                    }
                  })
}

computeRestartsForEmacs <- function (sldbState) {
  lapply(sldbState$restarts,
         function(x) {
           ## this is all a little bit internalsy
           restartName <- x[[1]][[1]]
           description <- restartDescription(x)
           list(restartName, if(is.null(description)) restartName else description)
         })
}

`swank:debugger-info-for-emacs` <- function(slimeConnection, sldbState, from=0, to=NULL) {
  list(list(as.character(sldbState$condition), sprintf("  [%s]", class(sldbState$condition)[[1]]), FALSE),
       computeRestartsForEmacs(sldbState),
       `swank:backtrace`(slimeConnection, sldbState, from, to),
       list(sldbState$id))
}

`swank:invoke-nth-restart-for-emacs` <- function(slimeConnection, sldbState, level, n) {
  if(sldbState$level == level) {
    invokeRestart(sldbState$restarts[[n+1]])
  }
}

`swank:frame-source-location` <- function(slimeConnection, sldbState, n) {
  call <- sldbState$calls[[n+1]]
  srcref <- attr(call, "srcref")
  srcfile <- attr(srcref, "srcfile")
  if(is.null(srcfile)) {
    list(quote(`:error`), "no srcfile")
  } else {
    filename <- get("filename", srcfile)
    ## KLUDGE: what this means is "is the srcfile filename
    ## absolute?"
    if(substr(filename, 1, 1) == "/") {
      file <- filename
    } else {
      file <- sprintf("%s/%s", srcfile$wd, filename)
    }
    list(quote(`:location`),
         list(quote(`:file`), file),
         list(quote(`:line`), srcref[[1]], srcref[[2]]-1),
         FALSE)
  }
}

`swank:buffer-first-change` <- function(slimeConnection, sldbState, filename) {
  FALSE
}

`swank:eval-string-in-frame` <- function(slimeConnection, sldbState, string, index) {
  frame <- sldbState$frames[[1+index]]
  withRetryRestart("retry SLIME interactive evaluation request",
                   value <- eval(parse(text=string), envir=frame))
  printToString(value)
}

`swank:frame-locals-and-catch-tags` <- function(slimeConnection, sldbState, index) {
  frame <- sldbState$frames[[1+index]]
  objs <- ls(envir=frame)
  if(identical(frame, globalenv())) {
    objs <- c()
  }
  list(lapply(objs, function(name) { list(quote(`:name`), name,
                                          quote(`:id`), 0,
                                          quote(`:value`),
                                          tryCatch({
                                            printToString(eval(parse(text=name), envir=frame))
                                          }, error=function(c) {
                                            sprintf("error printing object")
                                          }))}),
       list())
}

`swank:simple-completions` <- function(slimeConnection, sldbState, prefix, package) {
  literal2rx <- function(string) {
    ## list of ERE metacharacters from ?regexp
    gsub("([.\\|()[{^$*+?])", "\\\\\\1", string)
  }
  matches <- apropos(sprintf("^%s", literal2rx(prefix)), ignore.case=FALSE)
  nmatches <- length(matches)
  if(nmatches == 0) {
    list(list(), "")
  } else {
    longest <- matches[order(nchar(matches))][1]
    while(length(grep(sprintf("^%s", literal2rx(longest)), matches)) < nmatches) {
      longest <- substr(longest, 1, nchar(longest)-1)
    }
    list(as.list(matches), longest)
  }
}

`swank:compile-string-for-emacs` <- function(slimeConnection, sldbState, string, buffer, position, filename, policy) {
  lineOffset <- charOffset <- colOffset <- NULL
  for(pos in position) {
    switch(as.character(pos[[1]]),
           `:position` = {charOffset <- pos[[2]]},
           `:line` = {lineOffset <- pos[[2]]; colOffset <- pos[[3]]},
           warning("unknown content in pos", pos))
  }
  frob <- function(refs) {
    lapply(refs,
           function(x)
           srcref(attr(x,"srcfile"),
                  c(x[1]+lineOffset-1, ifelse(x[1]==1, x[2]+colOffset-1, x[2]),
                    x[3]+lineOffset-1, ifelse(x[3]==1, x[4]+colOffset-1, x[4]),
                    ifelse(x[1]==1, x[5]+colOffset-1, x[5]),
                    ifelse(x[3]==1, x[6]+colOffset-1, x[6]))))
  }
  transformSrcrefs <- function(s) {
    srcrefs <- attr(s, "srcref")
    attribs <- attributes(s)
    new <- 
      switch(mode(s),
             "call"=as.call(lapply(s, transformSrcrefs)),
             "expression"=as.expression(lapply(s, transformSrcrefs)),
             s)
    attributes(new) <- attribs
    if(!is.null(attr(s, "srcref"))) {
      attr(new, "srcref") <- frob(srcrefs)
    }
    new
  }
  withRestarts({
    times <- system.time({
      exprs <- parse(text=string, srcfile=srcfile(filename))
      eval(transformSrcrefs(exprs), envir = globalenv()) })},
               abort="abort compilation")
  list(quote(`:compilation-result`), list(), TRUE, times[3], FALSE, FALSE)
}

withRetryRestart <- function(description, expr) {
  call <- substitute(expr)
  retry <- TRUE
  while(retry) {
    retry <- FALSE
    withRestarts(eval.parent(call),
                 retry=list(description=description,
                   handler=function() retry <<- TRUE))
  }
}

`swank:interactive-eval` <-  function(slimeConnection, sldbState, string) {
  withRetryRestart("retry SLIME interactive evaluation request",
                   tmp <- withVisible(eval(parse(text=string), envir=globalenv())))
  if(tmp$visible) {
    prin1ToString(tmp$value)
  } else {
    "# invisible value"
  }
}

`swank:eval-and-grab-output` <- function(slimeConnection, sldbState, string) {
  withRetryRestart("retry SLIME interactive evaluation request",
                   { output <-
                       capture.output(tmp <- withVisible(eval(parse(text=string),
                                                              envir=globalenv()))) })
  output <- paste(output, sep="", collapse="\n")
  if(tmp$visible) {
    list(output, prin1ToString(tmp$value))
  } else {
    list(output, "# invisible value")
  }
}

`swank:interactive-eval-region` <- function(slimeConnection, sldbState, string) {
  withRetryRestart("retry SLIME interactive evaluation request",
                   tmp <- withVisible(eval(parse(text=string), envir=globalenv())))
  if(tmp$visible) {
    prin1ToString(tmp$value)
  } else {
    "# invisible value"
  }
}

`swank:find-definitions-for-emacs` <- function(slimeConnection, sldbState, string) {
  if(exists(string, envir = globalenv())) {
    thing <- get(string, envir = globalenv())
    if(inherits(thing, "function")) {
      body <- body(thing)
      srcref <- attr(body, "srcref")
      srcfile <- attr(body, "srcfile")
      if(is.null(srcfile)) {
        list()
      } else {
        filename <- get("filename", srcfile)
        ## KLUDGE: what this means is "is the srcfile filename
        ## absolute?"
        if(substr(filename, 1, 1) == "/") {
          file <- filename
        } else {
          file <- sprintf("%s/%s", srcfile$wd, filename)
        }
        list(list(sprintf("function %s", string),
                  list(quote(`:location`),
                       list(quote(`:file`), file),
                       list(quote(`:line`), srcref[[2]][[1]], srcref[[2]][[2]]-1),
                       list())))
      }
    } else {
      list()
    }
  } else {
    list()
  }
}

`swank:value-for-editing` <- function(slimeConnection, sldbState, string) {
  paste(deparse(eval(parse(text=string), envir = globalenv()), control="all"),
        collapse="\n", sep="")
}

`swank:commit-edited-value` <- function(slimeConnection, sldbState, string, value) {
  eval(parse(text=sprintf("%s <- %s", string, value)), envir = globalenv())
  TRUE
}

resetInspector <- function(slimeConnection) {
  assign("istate", list(), envir=slimeConnection)
  assign("inspectorHistory", NULL, envir=slimeConnection)
}

`swank:init-inspector` <- function(slimeConnection, sldbState, string) {
  withRetryRestart("retry SLIME inspection request",
                   { resetInspector(slimeConnection)
                     value <- inspectObject(slimeConnection, eval(parse(text=string), envir=globalenv()))
                   })
  value
}

inspectObject <- function(slimeConnection, object) {
  previous <- slimeConnection$istate
  slimeConnection$istate <- new.env()
  slimeConnection$istate$object <- object
  slimeConnection$istate$previous <- previous
  slimeConnection$istate$content <- emacsInspect(object)
  if(!(object %in% slimeConnection$inspectorHistory)) {
    slimeConnection$inspectorHistory <- c(slimeConnection$inspectorHistory, object)
  }
  if(!is.null(slimeConnection$istate$previous)) {
    slimeConnection$istate$previous$`next` <- slimeConnection$istate
  }
  istateToElisp(slimeConnection$istate)
}

valuePart <- function(istate, object, string) {
  list(quote(`:value`),
       if(is.null(string)) printToString(object) else string,
       assignIndexInParts(object, istate))
}

preparePart <- function(istate, part) {
  if(is.character(part)) {
    list(part)
  } else {
    switch(as.character(part[[1]]),
           `:newline` = list("\n"),
           `:value` = valuePart(istate, part[[2]], part[[3]]),
           `:line` = list(printToString(part[[2]]), ": ",
             valuePart(istate, part[[3]], NULL), "\n"))
  }
}

prepareRange <- function(istate, start, end) {
  range <- istate$content[start+1:min(end+1, length(istate$content))]
  ps <- NULL
  for(part in range) {
    ps <- c(ps, preparePart(istate, part))
  }
  list(ps, if(length(ps)<end-start) { start+length(ps) } else { end+1000 },
       start, end)
}

assignIndexInParts <- function(object, istate) {
  ret <- 1+length(istate$parts)
  istate$parts <- c(istate$parts, list(object))
  ret
}

istateToElisp <- function(istate) {
  list(quote(`:title`), deparse(istate$object, control="all", nlines=1),
       quote(`:id`), assignIndexInParts(istate$object, istate),
       quote(`:content`), prepareRange(istate, 0, 500))
}

emacsInspect <- function(object) {
  UseMethod("emacsInspect")
}

emacsInspect.default <- function(thing) {
  c(list(paste("a ", class(thing)[[1]], sep=""), list(quote(`:newline`))))
}

emacsInspect.list <- function(list) {
  c(list("a list", list(quote(`:newline`))),
    mapply(function(name, value) { list(list(quote(`:line`), name, value)) },
           names(list), list))
}

emacsInspect.numeric <- function(numeric) {
  c(list("a numeric", list(quote(`:newline`))),
    mapply(function(name, value) { list(list(quote(`:line`), name, value)) },
           (1:length(numeric)), numeric))
}

`swank:quit-inspector` <- function(slimeConnection, sldbState) {
  resetInspector(slimeConnection)
  FALSE
}

`swank:inspector-nth-part` <- function(slimeConnection, sldbState, index) {
  slimeConnection$istate$parts[[index]]
}

`swank:inspect-nth-part` <- function(slimeConnection, sldbState, index) {
  object <- `swank:inspector-nth-part`(slimeConnection, sldbState, index)
  inspectObject(slimeConnection, object)
}

`swank:inspector-pop` <- function(slimeConnection, sldbState) {
  if(!is.null(slimeConnection$istate$previous)) {
    slimeConnection$istate <- slimeConnection$istate$previous
    istateToElisp(slimeConnection$istate)
  } else {
    FALSE
  }
}

`swank:inspector-next` <- function(slimeConnection, sldbState) {
  if(!is.null(slimeConnection$istate$`next`)) {
    slimeConnection$istate <- slimeConnection$istate$`next`
    istateToElisp(slimeConnection$istate)
  } else {
    FALSE
  }
}

`swank:inspector-eval` <- function(slimeConnection, sldbState, string) {
  expr <- parse(text=string)[[1]]
  object <- slimeConnection$istate$object
  if(inherits(object, "list")|inherits(object, "environment")) {
    substituted <- substituteDirect(expr, object)
    eval(substituted, envir=globalenv())
  } else {
    eval(expr, envir=globalenv())
  }
}

`swank:inspect-current-condition` <- function(slimeConnection, sldbState) {
  resetInspector(slimeConnection)
  inspectObject(slimeConnection, sldbState$condition)
}

`swank:inspect-frame-var` <- function(slimeConnection, sldbState, frame, var) {
  resetInspector(slimeConnection)
  frame <- sldbState$frames[[1+frame]]
  name <- ls(envir=frame)[[1+var]]
  object <- get(name, envir=frame)
  inspectObject(slimeConnection, object)
}

`swank:default-directory` <- function(slimeConnection, sldbState) {
  getwd()
}

`swank:set-default-directory` <- function(slimeConnection, sldbState, directory) {
  setwd(directory)
  `swank:default-directory`(slimeConnection, sldbState)
}

`swank:load-file` <- function(slimeConnection, sldbState, filename) {
  source(filename, local=FALSE, keep.source=TRUE)
  TRUE
}

`swank:compile-file-for-emacs` <- function(slimeConnection, sldbState, filename, loadp, ...) {
  times <- system.time(parse(filename, srcfile=srcfile(filename)))
  if(loadp) {
    ## KLUDGE: inelegant, but works.  It might be more in the spirit
    ## of things to keep the result of the parse above around to
    ## evaluate.
    `swank:load-file`(slimeConnection, sldbState, filename)
  }
  list(quote(`:compilation-result`), list(), TRUE, times[3], substitute(loadp), filename)
}

`swank:quit-lisp` <- function(slimeConnection, sldbState) {
  quit()
}